A technique for analyzing the image of the face of the driver which is captured by using the near infrared light to detect the arousal level and inattentive driving of the driver and to utilize detection results for drive assist has been proposed. In order to detect the arousal level and the inattentive driving with high precision, it is desirable to capture the image of the face of the driver under a stable condition. However, when the image is captured relying on the near infrared light contained in sunlight, a condition under which the face of the driver is illuminated changes depending on weather or a time zone.
Under the circumstances, providing a first emission unit in the vicinity of a camera for capturing the image of the face, and emitting a near infrared light diagonally upward toward the face of the driver has been extensively conducted. With the above configuration, since the near infrared light can be always emitted from the first emission unit under the same condition, the face of the driver can be illuminated under the relatively similar condition regardless of the weather or the time zone. However, since the first emission unit illuminates the face from a lower side of the face, the amount of light in an upper side of the face is likely to become insufficient due to only the first emission unit. Further, when the face is illuminated from one direction, a shade is likely to be produced in the captured image. Under the circumstances, a technique for incorporating a second emission unit into the sunvisor to emit the near infrared light toward the face also from an upper side of the driver has been also proposed (PTL 1).
However, when the second emission unit that emits the near infrared light is incorporated into the sunvisor, such problems that not only a structure of the sunvisor is complicated, but also a harness for supplying power to the second emission unit of the sunvisor is required and a workload for assembling the harness is caused occur.